From Steve Karg:

* added additional value string enumerations from BACnet-2004
* removed vendor specific value string enumerations
* corrected some value strings enumerations that were incorrect
* refactored some common strings as strings + format
* refactored some value strings to use a reserved range and a 
proprietary range by using val_to_split_str function which now correctly 
shows the split range when a value is not matched.
* corrected some spelling errors
* converted some item text values to dissector registration
* added protocol tree for the BACnet tag headers
* added value strings tree display for some bit string BACnet properties
* added value strings tree display for some enumerated BACnet properties
* changed the conversion of signed, unsigned, and enumerated BACnet 
values to use ntohx functions.
* added proper handling for large values of signed, unsigned, and 
enumerated BACnet values.
* refactored BACnet Null and Boolean Tag tree
* refactored BACnet Real and Double Tag tree
* changed comments into functions for special tags
* changed some white space to match existing file style
* refactored tvb_reported_length to tvb_length_remaining to simplify
* corrected octet-string tree when length is zero
* refactored octet-string tree to use tvb_bytes_to_str
* corrected application tagged productions that were context tagged
* corrected context tagged productions that were application tagged
* corrected offset for BACnet character strings
* refactored some identical service request tree handling
* changed confirmed APDU to highlight the correct portion of the APDU
* changed some dissector registration values to display as decimal
* changed cast in call to iconv() to fix compiler warning
* corrected bit-wise AND in AtomicFile tree handling

packet-bvlc.c
* added error text in tree when encoded length doesn't match actual length

svn path=/trunk/; revision=14417

1 files changed, 11 insertions, 3 deletions

diff --git a/epan/dissectors/packet-bvlc.c b/epan/dissectors/packet-bvlc.c
index db50ccf8ba..aa7820a588 100644
--- a/epan/dissectors/packet-bvlc.c
+++ b/epan/dissectors/packet-bvlc.c
@@ -107,6 +107,7 @@ dissect_bvlc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	guint16 bvlc_length;
 	guint16 packet_length;
 	guint npdu_length;
+	guint length_remaining;
 	guint16 bvlc_result;
 	tvbuff_t *next_tvb;
 
@@ -121,6 +122,7 @@ dissect_bvlc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	bvlc_type =  tvb_get_guint8(tvb, offset);
 	bvlc_function = tvb_get_guint8(tvb, offset+1);
 	packet_length = tvb_get_ntohs(tvb, offset+2);
+	length_remaining = tvb_length_remaining(tvb, offset);
 	if (bvlc_function > 0x08) {
 		/*  We have a constant header length of BVLC of 4 in every
 		 *  BVLC-packet forewarding an NPDU. Beware: Changes in the
@@ -159,9 +161,15 @@ dissect_bvlc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 			bvlc_function, val_to_str (bvlc_function,
 				bvlc_function_names, "Unknown"));
 		offset ++;
-		proto_tree_add_uint_format(bvlc_tree, hf_bvlc_length, tvb, offset,
-			2, bvlc_length, "BVLC-Length: %d of %d bytes BACnet packet length",
-			bvlc_length, packet_length);
+		if (length_remaining != packet_length)
+			proto_tree_add_uint_format(bvlc_tree, hf_bvlc_length, tvb, offset,
+				2, bvlc_length, 
+				"BVLC-Length: %d of %d bytes (invalid length - expected %d bytes)",
+				bvlc_length, packet_length, length_remaining);
+		else		
+			proto_tree_add_uint_format(bvlc_tree, hf_bvlc_length, tvb, offset,
+				2, bvlc_length, "BVLC-Length: %d of %d bytes BACnet packet length",
+				bvlc_length, packet_length);
 		offset += 2;
 		switch (bvlc_function) {
 		case 0x00: /* BVLC-Result */